Delay powder



Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE GEORGE C. HALE, OI! THE UNITED STATES ARMY, 0F DOVER, NEW JERSEY DELAY POWDER No Drawing.

Application filed January 11, 1982. Serial No. 586,063.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The subject of this invention is a delay powder intended for use primarily in fuses and is a. modification of the powder disclosed in my prior Patent No. 1,805,214 of May 12, 1931.

In the patent, a uniform functioning delay powder for time train fuses is provided by a composition, one or more of the substances of which will decompose when decomposition is once started, and others of which will combine with the gases evolved on decomposition, the chemical reactions taking place evolving suflicient heat to insure a continuation of the reactions until the train is completely converted. The result of these chemical reactions is the production of solids rather than gases. The patent relates particularly to a powder embodying a metallic oxide, a mineral adapted to react with oxygen to form a solid and glycerine.

The slag resulting fromthe combustion of the metallic oxide powder is more or less fluid and its facility of movement under the action of centrifugal force due to rotation of the shell interferes with the combustion of the train and tends to obstruct communicating passages. This behavoir of the slag results in malfunctions and in a measure is the cause of comparatively wide variations in time of burning.

I have discovered that the employment of a metallic chromate in lieu of the oxide obviates the foregoing disadvantages, produces a less hygroscopic powder, gives a superior binding action that improves loading, and reduces the rate of burning.

As examples of the use of metallic oxides, the following compositions have been particularly successful.

. Ptii' cent No. 1. Lead oxide 44 Lead chromate 39 Silicon 16 Linseed oil 1 The above compositions, when loaded and tested as fuse trains, in precisely the same manner, give the following burning times, all of which are greater than when the metallic oxides are solely employed as oxidizing agents.

Seconds No.1 26.6 No. 2 Q. 29.5 No. 3 42.3

Other chromates, such as barium, strontium and iron can be substituted entirely or in part for the lead chromate in the preceding compositions but no advantage is gained from the standpoint of controlling the rate of burning of the powders since the rate of burning can be variedsufliciently for most practical purposes by altering the proportions of the ingredients in the powders listed above.

However a particular advantage obtained resides in the nature of the slags or residues resulting from combustion of powders con taining the different chromates. In employing such powders in various types of fuses, it is sometimes desirable to have the prod nets of combustion exist as solids rather than as liquids at the high temperature produced on combustion. Since the melting points of barium, strontium and iron are considerably higher than the melting point of lead, the production of the free metal in the liquid state is less liable to occur in the case of chromates of metals which have high melting points. The selection of a particular chromate will therefore depend on the character and type of fuse and the nature of its application.

Linseed oil is preferable to glycerine in these compositions as it gives better binding action and results in better loading and machining properties of the powder. The chromates, especially lead chromate, have binding qualities not present in the oxides.

It is to be understood that the metals em= ployed to react with oxygen may be interchanged and substituted.

I claim:

1. A delay powder including a metallic chromate, a metal adapted to react with oxygen to form a solid, and linseed oil.

2. A delay powder including a metallic chromate, a metal adapted to react with oxygen to form a solid, and a binder.

3. A delay powder including metallic chromates, a metal adapted to react with oxygen to form a solid, and a binder.

4. A delay powder including a metallic oxide and a metallic chromate in approximately equal amounts, and a metal adapted to react with oxygento form a solid.

5. A delay powder including a metallic oxide, a metallic chromate, and a metal adapted to react with oxygen to form a solid.

6. A delay powder including a chromate of lead, a metal adapted to react with oxygen to form a solid, and a binder.

7 A delay powder including a chromate 0i lead, and a metal adapted to react with oxygen to form a solid.

8. A delay powder including lead chromate 88 per cent, silicon 10 per cent, aluminum 1 per cent, and. linseed oil 1 per cent.

9. A delay powder including a metallic chromate 88 per cent, a metal adapted to react with oxygen to form a solid 11 per cent and a binder 1 per cent.

10. A delay powder including a metallic chromate 39-88 per cent, a metallic oxide 44-0 per cent, a binder 1 per cent, and the remainder a metal adapted to react with oxygen to form a solid.

- GEORGE C. HALE. 

